1. Field of the Invention
This invention generally relates to the field of optical alignment apparatus and, more particularly, to an apparatus for inducing fine adjustments to the alignment of a light beam along a desired axis.
2. Description of the Prior Art
In many applications where an optical beam is used to project a spot for the purpose of establishing a reference path or target point, the axis of the optical beam must be aligned with respect to another component or reference. By way of example, in applications employing a laser as a sighting device for a firearm, the laser spot formed by projecting the laser beam onto a target provides an indication of the impact point of the firearm projectile on that target. In such applications the laser is commonly mounted directly onto the firearm. To achieve coincidence between the laser spot and the projectile impact point, the laser beam must normally be aligned with respect to one or more points along the slightly parabolic trajectory of the projectile. To achieve this alignment, the laser beam itself must usually be precisely oriented with respect to the firearm, which establishes the trajectory of the projectile. This alignment of the laser with respect to the firearm is commonly achieved either by mechanisms that deflect the laser beam along a desired path, or by mechanisms that physically reorient the axis of the entire structure of the laser.
Typical mechanisms for providing fine adjustment to the axis of the laser structure are usually bulky in comparison to the size of the laser or lack the necessary degree of sensitivity for making sufficiently fine adjustments in the orientation of the laser housing. Beam deflection devices that achieve realignment of the laser beam by reflection of the beam are commonly more compact, but are usually costly due to the high cost of precision optical-quality components and may be sensitive to shock and vibration. In some applications both the laser and the alignment mechanism can be subjected to high levels of shock and vibration. Where a laser is used as an aiming device for a handgun or other firearm, the laser and alignment mechanism are normally subjected to considerable shock and vibration when the firearm is discharged.
Accordingly, there exists a need for a compact mechanism that maintains a stable alignment in the presence of high levels of shock and vibration, but is also compact and capable of creating minute changes in beam orientation.